As deformation rate increases, the thermally activated dislocation glide gives way to a continuous glide of dislocations governed by their interactions with phonons. Understanding the dislocation-phonon drag regime is critical for designing metallic materials for extreme deformations rates. However, it has proven challenging to study empirically, partly due to the resource intensive nature of the experimental approaches targeting this regime. Here, we develop an impression-based experimental approach combining laser-induced microprojectile impact (Hassani et al., 2020a) and spherical nanoindentation to characterize the dislocation-phonon drag regime. We also develop a physically based constitutive framework that, when integrated with our experimental measurements, can quantify the dislocation-phonon drag regime. We isolate the effect of dislocation-phonon drag by leveraging the similar deformation geometries and length scales but different operative mechanisms during spherical nanoindentation and microprojectile impact. We discuss mechanistic contributions to the plastic work for microprojectile impacts in a range of impact velocities producing strain rates up to 10 s. We also develop a deformation mechanism map focused on the transition from thermal activation to dislocation drag for a model FCC metal, copper.

中文翻译：

---

通过激光诱导微弹撞击量化高应变率下的位错阻力

随着变形率的增加，热激活位错滑移让位给由位错与声子相互作用控制的连续滑移。了解位错-声子阻力机制对于设计极端变形率的金属材料至关重要。然而，事实证明，实证研究具有挑战性，部分原因是针对该机制的实验方法具有资源密集性。在这里，我们开发了一种基于压印的实验方法，结合激光诱导微弹撞击（Hassani et al., 2020a）和球形纳米压痕来表征位错-声子阻力状态。我们还开发了一个基于物理的本构框架，当与我们的实验测量相结合时，可以量化位错-声子阻力状态。我们通过利用球形纳米压痕和微弹撞击期间相似的变形几何形状和长度尺度但不同的操作机制来分离位错-声子阻力的影响。我们讨论了在一系列冲击速度下产生高达 10 秒的应变率的微弹撞击塑性工作的机械贡献。我们还开发了一个变形机制图，重点关注模型 FCC 金属铜从热激活到位错阻力的转变。